In order to feed electrical energy from a power generating machine, e.g. a wind turbine, to an electricity network, it is typically necessary to adapt the frequency of the generated electrical power to an operating frequency of the electricity network.
For wind turbines there are known frequency converter arrangements, which use a number of identical inverter modules and/or converter modules in parallel in order to reach a desired capacity of electrical power. In the following these modules are referred to as electrical converter modules.
In case of a defect of one of the electrical converter modules the power generating machine must be stopped and the respective frequency converter must be disconnected from the electricity network until the defect electrical converter module has been exchanged. This is due to the fact that a failure within an electrical converter module is often caused by a short circuit in an Insulated Gate Bipolar Transistor (IGBT), which is a controlled power semiconductor. Therefore, the respective defect electrical converter module cannot only be disconnected logically but must be physically disconnected in order to allow the remaining electrical converter modules to continue their operation.
In many frequency converters being used for power generation machines, in particular for wind turbines, the electrical converter modules are placed like large books side by side on a shelf, bolted to the chassis and are equipped with bolted AC and DC main current connections. In case of a failure of already one of the electrical converter modules a removal of the respective module is a cumbersome procedure, which, as has already been described above, requires the power generation machine to stop its operation. Thereby, the downtime of the power generation machine is increased.
There may be a need for facilitating the disconnection of an electrical converter module within a frequency converter.